A wide variety of applications exist for portable tent-like structures which may be used to cover a designated area to provide protection from the sun or rain or both. Typical applications are for covers over spas, outdoor patio tables and chairs, pools, picnic areas, horse stalls, automobiles, weddings, or other social events, and the like. Some of these uses are for relatively short periods of times, whereas for others, the cover may be left in place for weeks or months at a time without being moved. Most temporary covers and those used as a sun shield or rain shield for automobiles, horse stalls and boats, require an overhead canopy or "roof" with open sides, since the covers are not used as a shelter or living area, but primarily are used for protection from sun and rain.
In the past, various types of portable or temporary covers have been developed, but such covers either lack the desired simplicity of assembly and disassembly or do not provide for a wind proof holding down of the fabric placed over the frame of the structure. A number of patents directed to generally rectangular pole/roof structures over which a tent or roof of flexible material is placed, have been issued. Typical of these patents are the Patents to Wickstrum U.S. Pat. No. 1,792,690; Lemen U.S. Pat. No. 2,513,729; Williams U.S. Pat. No. 2,535,618; Collins U.S. Pat. No. 2,835,262; Kirkham U.S. Pat. No. 3,699,986; and Lynch U.S. Pat. No. 4,641,676.
In the Williams Patent, the tent material is secured to horizontal poles of an underlying free-standing frame by means of screws which extend through grommets in the fabric. This produces a secure means of fastening the fabric to the frame, but assembly and disassembly is quite time consuming. Some of the other patents simply illustrate the fabric as being placed over the top of the poles and these structures employ fabric with a "boxed" or downwardly depending edge to fit over the corners formed by the junctions of the vertical and horizontal members of the underlying pole frame. Without some interconnection, however, between the fabric and the frame, it is possible for a slight breeze to blow the fabric cover partially or completely off the frame.
The Patent to Kirkham discloses a number of different tent modules which may be interconnected together to form larger structures in a variety of different configurations. Kirkham, however, does not employ a freestanding pole structure or frame structure, but it is necessary for the fabric or tent material to be staked to the ground in order to provide structural rigidity or integrity to the shelter.
Other frame and fabric arrangements have long been used for tents of the type used by campers and back-packers. Some of these structures employ an internal frame which is erected inside a pre-shaped enclosed tent. Others employ a similar frame structure, but which is placed outside the tent material. The tent material then is suspended from the external frame. Typically, tent structures of this type are relatively small in size.
It is desirable to provide a portable shelter which overcomes the disadvantages of the prior art discussed above, which is simple to assemble and dismantle, and which provides a secure interconnection between the frame and the fabric with a minimum of effort.